This invention relates to communication of vehicular deceleration information to following vehicles, especially in automotive vehicles having the U.S. Federal Government-mandated "center high-mounted stoplight" system.
Following a series of tests in which the benefits of additional signaling to the driver of a trailing motor vehicle were illustrated in a convincing manner the U.S. Government, since the mid 1980's, has mandated the incorporation of high-mounted braking indication signals at the rear of newly manufactured motor vehicles. This new signal which is often mounted at eye level in a laterally centered lower or upper portion of the vehicle rear window has become known in the art as a "center high-mounted stoplight" system. References to the system by a name of this nature, in fact, appear in government vehicle specifications. Earlier versions of this system used one or more incandescent filament lamps (within a module carried inside the vehicle on the rear shelf for example) as a source of signal illumination. Later appearing versions have included an array of physically dispersed incandescent filament or light-emitting diode devices disposed outside the vehicle and spread over significant rear facing dimensions of the vehicle. In either instance the signaling device is required to meet detailed standards regarding viewing angle and other details.
One of the origins of apparatus of this type is found in a study accomplished over ten years ago, a study in which an additional brake light was placed high and centered on 2100 taxicabs in Washington, D.C. (see Malone, 1986, one of the reference publications identified subsequently herein). During this study it was found that the number of rear-end collisions with these taxicabs was significantly (p=0.001) reduced--by 54%. The results were so compelling that all cars since September 1985 now incorporate this feature. Rear-end accidents account for about 37% of all multi-vehicle accidents (McKnight reference, 1992). The present invention further enhances this proven system by flashing the center high-mounted rear stoplight when the vehicle is undergoing an abrupt, relatively high-g deceleration or stop.
Another origin for systems of the present type lies in the fact that flashing lights are known to have better visual attention-getting attributes than steady state lights. Emergency vehicles use flashing lights to increase conspicuity and to warn of potentially dangerous situations for this reason. This is also why aircraft anti-collision lights (both on aircraft and on high towers or buildings) are flashed. Inherently, some drivers manually turn on their emergency flashers to provide short and long-range warning to oncoming traffic of traffic slow down in recognition of this visibility improvement. The system of the present invention will serve to automatically warn drivers behind rapidly decelerating vehicles to take precautionary measures. If ultimately used in large numbers of vehicles on the road, a system of this type will provide a universally recognizable indication of rapid vehicle decelerations and the need for following driver alertness to unforeseen traffic conditions.
The U.S. Government owns, maintains and uses large numbers of motor vehicles. The present invention stoplight enhancement system will likely reduce the number of rear-end collisions occurring with these vehicles thereby saving lives, money and government property. Universal use of the invention by cars, vans and small trucks is believed to offer the potential for increased overall traffic safety on national (or even international) highways.